Cod sursa(job #205955)

Utilizator MisterXGrigore MisterX Data 3 septembrie 2008 18:28:34
Problema Fractii Scor 0
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.32 kb
Raporteaza aceasta sursa 
#include<stdio.h>
 long long n,i,j,a[1000000];
 int main()
{
 freopen("fractii.in","rt",stdin);
 freopen("fractii.out","wt",stdout);
 scanf("lld",&n);
 for(i=1;i<=n;++i)
 a[i]=i-1;
 for(i=2;i<=n;++i)
 for(j=i*2;j<=n;j+=i)   
 a[j]-=a[i];
 for (i=0,j=0;i<=n;j+=a[i]) ++i;
 printf("%lld",j*2+1);
 return 0;
 }